An islanding detection method based on adaptive reactive power disturbance

Islanding detection is an essential function of distributed grid-connected power generation systems, and an islanding detection method based on adaptive reactive power disturbance is proposed in this article. Importing the reactive power disturbance can make RLC loads generate the frequency shift when the power grid is disconnected for fault and the islanding will be detected. The reactive power disturbance is combined with reactive power change and frequency variation, and reactive power change and frequency variation are closely nearby zero when the energy router is connected with the grid. So the total harmonic distortion (THD) of connected current will be very low and the great power quality will be assured in the proposed islanding detection method. In addition, the relation between new energy capacity and load capacity is established in this method. The quantitative analysis of reactive power disturbance is carried out and verified in MATLAB/Simulink simulation. The simulation results show that the islanding detection method based on reactive power disturbance can detect the isolated island phenomenon within the 0.1s under the setting parameters. It can not only satisfy the speed and accuracy, but also reduce the disturbance of power grid.